1. Technical Field
Embodiments of the invention generally relate to micromachined transducer arrays, and more specifically pertain to structures for providing flexibility of such arrays.
2. Background Art
Transducer devices typically include a membrane capable of vibrating in response to a time-varying driving voltage to generate a high frequency pressure wave in a propagation medium (e.g., air, water, or body tissue) in contact with an exposed outer surface of a transducer element. This high frequency pressure wave can propagate into other media. The same piezoelectric membrane can also receive reflected pressure waves from the propagation media and convert the received pressure waves into electrical signals. The electrical signals can be processed in conjunction with the driving voltage signals to obtain information on variations of density or elastic modulus in the propagation media.
Transducer devices can be advantageously fabricated inexpensively to exceedingly high dimensional tolerances using various micromachining techniques (e.g., material deposition, lithographic patterning, feature formation by etching, etc.). Such arrayed devices include micromachined ultrasonic transducer (MUT) arrays such as capacitive transducers (cMUTs) or piezoelectric transducers (pMUTs), for example.
Many ultrasound applications—such as intravascular ultrasound (IVUS), endoscopic ultrasound (EUS) or other medical sonography techniques—use catheters or other such instruments having non-planar surfaces. Typically, transducer arrays are positioned to avoid, or sized to accommodate, a somewhat small radii of curvature (e.g. ˜5-10 mm) of such non-planar surfaces. However, as successive generations of such instruments continue to scale in size, there is an attendant push for transducer arrays to support operation on surfaces having smaller radii of curvature.